This study examined the link between exposure to particulate matter—a form of air pollution in which fine particles are suspended in the air—and adverse health outcomes for the elderly, who are hypothesized to be affected disproportionately. In order to continue to determine environmental standards for pollution and to design effective public health warnings about pollution, an understanding of the health effects is needed. Such policies are particularly pertinent to the elderly, who might be socially isolated and less able to leave an area during a high-pollution episode. In contrast to previous studies, the researchers did not find an effect of particulate matter (PM) on the health outcomes examined (cardiovascular hospital admissions, all respiratory admissions, and admissions for myocardial infarction). However, the findings do not imply that PM does not affect these health outcomes, as the confidence intervals do not rule out effects comparable to those found in previous research.